This invention deals with timers, and more specifically with appliance cycle timer control mechanisms and drive mechanisms.
As the variety of demands made upon modern appliances has increased, so have the requirements made upon appliance cycle timers. For example, modern washing machines capable of washing various types of synthetic fabrics must be able to follow relatively complex washing cycle instructions in order properly to wash such synthetic fabrics. Appliances must be capable of carrying out such cycles without being attended by an operator.
As the cycle timer requirements have become more complex and demanding, cycle timers have, of course, become more complex to manufacture, adjust and install in the appliances. This increased complexity has resulted in increased cost. Further, in order to house the necessary equipment to achieve the complex cycles demanded, it has been necessary either to increase the size of appliance timers or, if the external size of the timer is required to remain constant, to decrease the size of the various internal timer components. Such a decrease in size can result in more fragile timer internal components which are more susceptible to breakage during appliance operation. Additionally such small components are frequently more expensive to manufacture and assemble, further adding to appliance cost.
Miniaturization of many appliance timer components has also been limited by the increased demand which modern appliances frequently place upon such timer components as, for example, on-off switches. Many of the necessary switches in appliance timers are now required to carry higher currents than they have in past appliances due to the increased work which the appliances are required to do. For example, the larger washing machines of today must carry larger loads of washing through a number of washing and spinning cycles. The size of the wash load often requires that the electric motor used in the washer be a higher current motor. Motor current may have to be switched several times by on-off switches housed within the appliance timer during the washing cycle.
Accordingly, it is an object of the present invention to provide an appliance cycle timer which is simple and economical to manufacture, and which incorporates an ample amount of program timing capacity to provide the required complex cycling.
It is a further object of the present invention to provide such a cycle timer in which the cycle-controlling switches have sufficient capacity to handle the relatively high-current requirements of modern appliances, and yet remain simple and economical to manufacture.
It is a further object of the present invention to provide such a cycle timer in which connections to the various switches are readily accessible from outside the timer housing, allowing the switch components to be wired in various combinations to meet the cycle timing requirements of a multiplicity of applications.
An additional object of the present invention is to provide a timer for controlling the operating cycle of an appliance, the timer including first means providing a program wheel mounted for rotation, switching means for initiating the various portions of the appliance operating cycle, means for driving the first means to rotate the program wheel in a predetermined manner, the wheel having a plurality of concentric and continuous grooves in its surfaces, the bottom of each groove defining a program controlling surface, and means for following each program controlling surface, the following means being coupled to the switching means for controlling the operating cycle of the appliance, and each following means extending into its respective groove.
A further object of the present invention is to provide such an apparatus wherein the pole and throw members of each of the switching means are formed from lengths of resilient wire having proximal ends fixedly mounted in a terminal block and accessible from the outside of the apparatus housing so that the various switch members may be coupled to one another readily to adapt the timer to a particular timing application.
Another object of the present invention is to provide such an apparatus wherein the distal ends of the throw members of the switches are formed to provide the following means, which following means are retained in the grooves, the throw members being formed and mounted yieldably to urge the following means against the groove bottoms to maintain contact spacing and alignment.
It is a further object of the present invention to provide an appliance cycle timer wherein the first means is generally disc-shaped and provides two opposite, axially facing program wheel sides, each side being provided with a plurality of grooves.
Another object of the present invention is to provide such an appliance cycle timer including an escapement mechanism comprising a drive member rotatable about an axis and providing a camming surface, means for following the camming surface, means for urging the following means into contact with the camming surface, an output shaft, a ratchet wheel drivingly connected to the output shaft, a pawl for engaging the ratchet wheel, the pawl being coupled to the following means and actuable by the following means to move the pawl a predetermined distance in a first direction, then return the pawl the same distance in the opposite direction to advance the ratchet wheel and output shaft a predetermined amount in response to rotation of the drive member.
An additional object of the present invention is to provide such an escapement mechanism wherein the driving member is generally cylindrical and is rotatable upon its axis and the camming surface comprises at least one cam lobe extending radially inwardly and peripherally about the inner cylindrical wall of the driving member.
A further object of the present invention is to provide such an escapement mechanism wherein the ratchet wheel and pawl are disposed within the cylindrical driving member and the ratchet wheel and driving member are coaxial with the output shaft.
Another object of the present invention is to provide such an escapement mechanism wherein the means for urging the following means into contact with the camming surface is a cardioid spring having a loop disposed about the driving member axis of rotation to position the spring within the escapement mechanism, the ends of the spring resting against the following means for urging the following means radially outwardly against the camming surface.
Other and further objects of the present invention will become apparent to those skilled in the art to which this invention pertains by referring to the following description and the accompanying drawings in which: